JDK1.8版本AbstractSequentialList源码如下：
package java.util;
public abstract class AbstractSequentialList<E> extends AbstractList<E> {
/**
* Sole constructor. (For invocation by subclass constructors, typically
* implicit.)
*/
protected AbstractSequentialList() {
}
/**
* Returns the element at the specified position in this list.
*
* <p>This implementation first gets a list iterator pointing to the
* indexed element (with <tt>listIterator(index)</tt>). Then, it gets
* the element using <tt>ListIterator.next</tt> and returns it.
*
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E get(int index) {
try {
return listIterator(index).next();
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
/**
* Replaces the element at the specified position in this list with the
* specified element (optional operation).
*
* <p>This implementation first gets a list iterator pointing to the
* indexed element (with <tt>listIterator(index)</tt>). Then, it gets
* the current element using <tt>ListIterator.next</tt> and replaces it
* with <tt>ListIterator.set</tt>.
*
* <p>Note that this implementation will throw an
* <tt>UnsupportedOperationException</tt> if the list iterator does not
* implement the <tt>set</tt> operation.
*
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E set(int index, E element) {
try {
ListIterator<E> e = listIterator(index);
E oldVal = e.next();
e.set(element);
return oldVal;
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
/**
* Inserts the specified element at the specified position in this list
* (optional operation). Shifts the element currently at that position
* (if any) and any subsequent elements to the right (adds one to their
* indices).
*
* <p>This implementation first gets a list iterator pointing to the
* indexed element (with <tt>listIterator(index)</tt>). Then, it
* inserts the specified element with <tt>ListIterator.add</tt>.
*
* <p>Note that this implementation will throw an
* <tt>UnsupportedOperationException</tt> if the list iterator does not
* implement the <tt>add</tt> operation.
*
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public void add(int index, E element) {
try {
listIterator(index).add(element);
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
/**
* Removes the element at the specified position in this list (optional
* operation). Shifts any subsequent elements to the left (subtracts one
* from their indices). Returns the element that was removed from the
* list.
*
* <p>This implementation first gets a list iterator pointing to the
* indexed element (with <tt>listIterator(index)</tt>). Then, it removes
* the element with <tt>ListIterator.remove</tt>.
*
* <p>Note that this implementation will throw an
* <tt>UnsupportedOperationException</tt> if the list iterator does not
* implement the <tt>remove</tt> operation.
*
* @throws UnsupportedOperationException {@inheritDoc}
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E remove(int index) {
try {
ListIterator<E> e = listIterator(index);
E outCast = e.next();
e.remove();
return outCast;
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
// Bulk Operations
/**
* Inserts all of the elements in the specified collection into this
* list at the specified position (optional operation). Shifts the
* element currently at that position (if any) and any subsequent
* elements to the right (increases their indices). The new elements
* will appear in this list in the order that they are returned by the
* specified collection's iterator. The behavior of this operation is
* undefined if the specified collection is modified while the
* operation is in progress. (Note that this will occur if the specified
* collection is this list, and it's nonempty.)
*
* <p>This implementation gets an iterator over the specified collection and
* a list iterator over this list pointing to the indexed element (with
* <tt>listIterator(index)</tt>). Then, it iterates over the specified
* collection, inserting the elements obtained from the iterator into this
* list, one at a time, using <tt>ListIterator.add</tt> followed by
* <tt>ListIterator.next</tt> (to skip over the added element).
*
* <p>Note that this implementation will throw an
* <tt>UnsupportedOperationException</tt> if the list iterator returned by
* the <tt>listIterator</tt> method does not implement the <tt>add</tt>
* operation.
*
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public boolean addAll(int index, Collection<? extends E> c) {
try {
boolean modified = false;
ListIterator<E> e1 = listIterator(index);
Iterator<? extends E> e2 = c.iterator();
while (e2.hasNext()) {
e1.add(e2.next());
modified = true;
}
return modified;
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
// Iterators
/**
* Returns an iterator over the elements in this list (in proper
* sequence).<p>
*
* This implementation merely returns a list iterator over the list.
*
* @return an iterator over the elements in this list (in proper sequence)
*/
public Iterator<E> iterator() {
return listIterator();
}
/**
* Returns a list iterator over the elements in this list (in proper
* sequence).
*
* @param index index of first element to be returned from the list
* iterator (by a call to the <code>next</code> method)
* @return a list iterator over the elements in this list (in proper
* sequence)
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public abstract ListIterator<E> listIterator(int index);
}
